/*
 * Copyright (C) 2009 Leandro Aparecido <lehphyro@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.metalframework.util;

import java.lang.annotation.*;
import java.lang.reflect.*;
import java.util.*;

public abstract class AnnotationUtils {

	public static <A extends Annotation> A getAnnotation(AnnotatedElement element, Class<A> annotationType) {
		A annotation = element.getAnnotation(annotationType);
		
		if (annotation == null) {
			for (Annotation a : element.getAnnotations()) {
				annotation = getAnnotationOnAnnotation(a, annotationType);
				if (annotation != null) {
					break;
				}
			}
		}
		
		return annotation;
	}
	
	@SuppressWarnings("unchecked")
	public static <A extends Annotation> List<A> getParameterAnnotations(Method method, Class<A> annotationType) {
		Annotation[][] parameterAnnotations = method.getParameterAnnotations();
		List<A> annotations = new ArrayList<A>(); 
		
		for (int i = 0; i < parameterAnnotations.length; i++) {
			A aux = null;
			for (Annotation a : parameterAnnotations[i]) {
				if (a.annotationType() == annotationType) {
					aux = (A)a;
					break;
				}
				aux = getAnnotationOnAnnotation(a, annotationType);
				if (aux != null) {
					break;
				}
			}
			annotations.add(aux);
		}

		return annotations;
	}
	
	public static <A extends Annotation> A getAnnotationOnAnnotation(Annotation annotation, Class<A> annotationType) {
		return annotation.annotationType().getAnnotation(annotationType);
	}
}
